Template Method Design Pattern in JAVA

/*
 * Requirement: Get the running time of a program
 * Principle: Get the start and end times of the program and subtract them
 *
 * Get time: through System.currentTimeMillis();
 * When the code is optimized, such problems can be solved
 * This method, the template method design pattern
 *
 * What is a template method
 * When defining a function, part of the function is deterministic, part is indeterminate, and the determinate part is using the indeterminate part
 * Then the uncertain part will be exposed at this time, and the subclass of the class will complete it
 *
 *
 * */

abstract class GetTime {
	public final void getTime() {
		long start = System.currentTimeMillis();
		runcode();
		long end = System.currentTimeMillis();
		System.out.println("毫秒：" + (end - start));
	}

	public abstract void runcode();
}

class SubTime extends GetTime{
	public void runcode(){
		for (int x = 0; x < 4000; x++) {
			System.out.println(x);
		}
	}
}

public class TemplateDemo {

	public static void main(String args[]) {
		SubTime gt = new SubTime();
		gt.getTime();
	}

}

                                                                                -----------------------By chick